At least three people have died and dozens were trapped when an Islamic boarding school building collapsed in Indonesia's East Java province, officials said Tuesday.

"The number of victims is 102 people, consisting of 99 survivors, 3 deaths," National Search and Rescue Agency head Mohammad Syafii said.

National Disaster Mitigation Agency (BNPB) spokesman Abdul Muhari added that rescuers were still searching for 38 people thought to be trapped under the rubble.

The building collapsed beneath the weight of the fourth floor which was under construction at the time of the accident. The building's expansion had not been authorized, according to provincial police spokesperson Jules Abraham Abast. 

Dozens of students had been taking part in afternoon prayers when the building collapsed. 

"This sudden occurrence caused building material to fall on dozens of students and workers," BNPB spokesperson Abdul Muhari said.

What do we know about the rescue operation?

Rescue officials were providing oxygen and water to students who were still trapped under the rubble as they worked to free the survivors, over 12 hours after the accident occurred.

"We have been running oxygen and water to those still trapped under the debris and keeping them alive while we work hard to get them out," said Nanang Sigit, the rescue officer leading the efforts.

He said that rescuers had seen several bodies under the rubble but were focused on saving those who were still alive. 

Hundreds of disaster workers, police officials and soldiers worked through the night to dig the survivors out. They temporarily suspended work at 10:15 am on Tuesday when the building shook, raising fears it could collapse further.

While heavy machinery was on site to aid the efforts, it was not being used due to the unstable conditions.

What do we know about the missing students?

Images from local media showed families of students gathered at hospitals and at the school site, anxiously looking through a white board for news of their children.

The Associated Press reported that the school board showed 65 children still missing as of Tuesday morning, with most of them boys between the ages of 12 and 17. 

Edited by: Karl Sexton